Plain lamp



FIG. 1 is a top plan view of a plain lamp showing my new design;

FIG. 2 is a rear elevational view thereof; a front elevational view isthe same;

FIG. 3 is a right side elevational view; a left side elevational view isidentical as a right side elevational view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front perspective right side view thereof; and,

FIG. 6 is a front perspective left side view thereof.

The ornamental design for a plain lamp, as shown and described.